The present invention generally relates to methods and devices for emergency calling, and more specifically, to the area of wireless call-for-help systems.
A call-for-help system is generally regarded as a communications system (normally a telephone that has been modified in some manner) used by a person to summon help when the person is in a situation in which that person is unable to either dial or conveniently access the call-to-help system. In general, there are two types of system architectures in use at the present time, an individual dialer box system architecture and a global wireless receiver system architecture. According to the individual dialer box system architecture, a dialer box responsive to a pendant is provided for each individual. The dialer box contains a radio frequency (RF) receiver and a speakerphone, and the pendant contains an RF transmitter. The RF receiver is configured to receive a signal from the pendant's RF transmitter, cause a speakerphone to go off-hook, and dial a preconfigured telephone number of a caregiver, such as an emergency response team or some central location. When the caregiver, party, or device at the other end answers, the caregiver can have a conversation with the caller by means of the hands-free speakerphone that is built into the dialer. The pendant may be carried by the person so that it may activate the RF receiver from the person's immediate location.
The hands-free speakerphone is important to the process because the person calling for help may be incapacitated and unable to pick up a standard phone set. However, a disadvantage of this type system is that transmitter only works in close proximity to the receiver/dialer. For persons confined to a small area, this may provide sufficient notification capability. However, if the person is capable of moving through various locations within a large area, then the person may move beyond the range of the transmitter and/or move beyond the range of the receiver/dialer.
A second type of system architecture, the global wireless receiver system architecture, may also be used to provide call-for-help capabilities. According to this system architecture, a network of RF receivers is incorporated throughout an area, or facility, in which the caller is located. This may allow a wireless transmitter to be activated anywhere in the facility by any pendant, as long as the receivers are placed in strategic locations to provide broad coverage throughout all areas of the facility. System architecture allows a signal from the caller's pendant to be received anywhere within the facility, and the caller's location can be determined from that signal. However, there is no possibility of a two-way voice communication since the signal is not associated with a telephone line; such system architectures employ either wireless repeaters positioned throughout the facility or else receivers attached to a central computer via RS-485 communications links, neither of which support voice links.
Another type of system architecture attempts to combine the best features of the previous two system architectures by placing a dedicated speakerphone in the person's apartment or residence, which responds to a call placed from a central location in receipt of a signal from the person's pendant. At the central location a determination is made of which pendant is issuing the signal and a caregiver dials in to the speakerphone, which automatically opens a line upon receipt of the call.
However, the problem with this arrangement is the criteria for selectively going off-hook. If the person is in a public area, then dedicated speakerphones could be employed to unconditionally go off-hook, but in the person's residence, other telephone devices, such as fax machines, voice answering machines, voice-mail services, and the like, may be connected with the incoming phone line. These devices typically employ a method of automatically going off-hook in response to incoming calls after a specified number of rings. In a residential application, the provision to have a hands-free speakerphone pick up after a designated number of rings may conflict with these other devices that are also programmed to answer after a specified number rings. Some systems have tried to overcome this limitation by employing a separate RF signal issued from the central location, which causes the speakerphone to go off-hook by remote command. However, this adds cost and complexity to the speakerphone device.
As can be seen, there is a need for a method and system to provide a hands-free speakerphone capability that identifies and responds to an incoming call made by a emergency caregiver while at the same time allowing other telephone devices to be used on the same telephone line.